Summary

When using google-antigravity provider (Cloud Code Assist), requests fail with a schema validation error for the cron tool (tool index #9).

Error Message

Cloud Code Assist API error (400): {
  "error": {
    "code": 400,
    "message": "{\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"tools.9.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at https://docs.claude.com/en/docs/tool-use.\"},\"request_id\":\"req_vrtx_011CWqrgWryHbJJhnzxirXcr\"}",
    "status": "INVALID_ARGUMENT"
  }
}

Root Cause

The cron tool schema in src/agents/tools/cron-tool.ts has complex nested structures that pass Anthropic's direct API validation but fail Google Cloud Code Assist's stricter JSON Schema draft 2020-12 enforcement:

1. Deeply nested anyOf unions - CronScheduleSchema, CronPayloadSchema, sessionTarget, wakeMode, channel all use TypeBox Type.Union() which compiles to anyOf
2. Mixed additionalProperties - false inside nested objects but true at the root level
3. minLength: 1 constraints on strings via NonEmptyString

The cleanSchemaForGemini() function in src/agents/pi-tools.ts attempts to normalize schemas but doesn't fully handle these nested union cases.

Workaround

Adding cron to the tool deny list allows google-antigravity to work:

{
  "agent": {
    "tools": {
      "deny": ["cron"]
    }
  }
}

Suggested Fix

Either:

1. Simplify the CronToolSchema to avoid deeply nested unions (flatten to a single object with optional fields)
2. Enhance cleanSchemaForGemini() to recursively simplify nested anyOf structures
3. Add provider-specific schema transformations for google-antigravity

Environment

• Clawdbot version: 2026.1.5-3
• Provider: google-antigravity
• Model: claude-opus-4-5-thinking